Identify A, B, C, D, E, R and `R^(1)` in the following:

Explanation

`C=RMgBr " "R=CH_(3)underset(|)CHCH_(3)`
`R^(1)=H_(3)C-underset(CH_(3))underset(|)overset(CH_(3))overset(|)C " " D=H_(3)C-underset(CH_(3))underset(|)overset(CH_(3))overset(|)C-MgX " " E=H_(3)C-underset(CH_(3))underset(|)overset(CH_(3))overset(|)C-H`